Many electrically-powered assemblies and devices, such as luminaire assemblies, are hung from ceilings or other supporting structures. In order for a luminaire assembly to be hung, the weight of the luminaire assembly must be supported from the supporting structure. In addition, in order to provide light, the luminaire assembly must be provided with power.
Many kinds of supports have been developed to suspend luminaire assemblies and to provide them with power. In recent years, conductive suspension cable systems have been developed for suspending and powering low voltage lighting fixtures, such as light-emitting diode (LED) luminaires, via conductive suspension cables, while also allowing height adjustability during installation via the usage of cable grippers. This development has allowed the adjustable suspension of luminaire assemblies of up to 100 pounds working load (500 pounds break strength), without the need for a separate power cord.
Architects, designers, and homeowners often consider a variety of lighting fixtures when designing the interior of a property and in many instances may prefer luminaire assemblies with adjustable suspension systems that require fewer suspension cables than those of other luminaire assemblies. This preference may be for aesthetic purposes or to provide lighting suspended from a smaller area on a ceiling.
However, each luminaire assembly may require at least two conductors. Prior suspension cable systems have been able to power luminaire and other electrical assemblies with cords that utilize two conductors. However, these prior suspension cable systems may not allow adjustability using cable grippers because cable grippers are designed to grip only one cable at a time and because cable grippers need to come into direct and conductive contact with a metallic cable to be effective. The first reason for these constraints is that when a cable gripper is used on a non-metallically insulated cable, its ball bearings or other gripper mechanism which surrounds and applies lateral compression upon the gripped cable, would likely tear the insulation while a user attempts adjustment, which would lodge the metallic ball bearings against the conductor itself, defeating the purpose of the insulation. Additionally, even if tearing does not occur, the gripper may easily slip on the non-metallic insulation, which would defeat the purpose of the gripper. Therefore, prior suspension systems that provide adjustability with cable grippers have required at least two single-conductor suspension cables.
Some suspension systems, such as those utilizing a crimp system, have provided limited adjustability to the height of suspended fixtures during installation. However, these options may be unattractive for various reasons. For example, adjustment of a suspension cable may require cutting and restriping a suspension cable, which may render useless the previously used crimp.